title: Calcium sensitizers isolated from the edible pine mushroom, Tricholoma matsutake (S. Ito & Imai) Sing.
abstract: Three lactam compounds were isolated from the fruiting body of Tricholoma matsutake (S. Ito & Imai) Sing., an edible mushroom, and their structures were identified as cyclo-S-proline-R-leucine (1), hexahydro-2H-azepin-2-one (2), and butyl 5-oxo-2-pyrrolidine carboxylate (3) by chemical, physicochemical, and spectral evidence. In in vitro screening tests, compounds 1 and 2 acted as calcium sensitizers in ventricular cells from rat. Further studies on compounds 1 and 2 in ex vivo isolated right atria showed positive inotropic effects without disturbing the spontaneous beating rate. The inotropic effect of compounds 1 and 2 could be greatly abolished by pretreating the myocardium in Ca(2+)-free solution. These findings indicate that compounds 1 and 2 can significantly increase the calcium ion concentration ([Ca2+]i) in myocytes, which is greatly dependent on the influx of extracellular Ca2+.
authors.affiliation: Harbin Medical University, School of Pharmacy, Harbin 150081, PR China.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Hou
authors.forename: Shichao
authors.initials: S
authors.lastname: Sun
authors.forename: Lijun
authors.initials: L
authors.lastname: Wu
authors.forename: Xiaodan
authors.initials: X
authors.lastname: Wang
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Minyun
authors.initials: M
authors.lastname: Zhang
authors.forename: Jianwei
authors.initials: J
authors.lastname: Wang
authors.forename: Libo
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D002118:Calcium / Q000819:agonists*; D002851:Chromatography, High Pressure Liquid; D006352:Heart Ventricles / Q000166:cytology / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization; D055439:Tricholoma / Q000737:chemistry*
chemical_list: D002118:Calcium